AMD’s next-gen upscaler is reportedly stretching far beyond its intended hardware. Users claim they’ve enabled FSR 4 on a Radeon RX 6800 XT—an RDNA 2 graphics card that isn’t officially supported—by using a modded DLL and the INT8 path included in the recently surfaced code. The result? Noticeably cleaner image quality than FSR 3, but with a bigger performance hit on older GPUs.
According to a user test on a popular hardware forum, FSR 4.0.2 with “Model 3” was activated in Stellar Blade via OptiScaler. In FSR 3 Quality mode, the game was running over 110 FPS. Swapping to FSR 4 Quality mode brought frame rates down to around 100–107 FPS, roughly a 10–20% drop depending on the scene, while improving perceived detail and overall upscaling clarity.
Why the larger penalty on RDNA 2? FSR 4 is designed to take advantage of newer hardware features. On RDNA 4-based cards (RX 9000 series), users typically see a modest 2–4% cost when enabling FSR 4. RDNA 3 tends to land in the 7–10% range. RDNA 2 lacks WMMA (Wavefront Matrix Multiply Accumulation) instructions, so matrix math has to be emulated through other capabilities such as DP4a or integer units, which introduces extra overhead and eats into frame rates.
The workaround hinges on using the INT8 variant rather than FP8. Many GPUs, including select AMD and NVIDIA models, can process INT8 efficiently, which is why experimenters also report success running these modded files on Radeon RX 7000 cards and GeForce RTX 30 series hardware. While performance varies based on the game and settings, the consistent takeaway is that FSR 4’s image quality uplift is real—even when hardware falls outside the official support list.
For gamers on RDNA 2, the trade-off is straightforward: if your frame rate headroom is already well into triple digits, enabling FSR 4 could be worth it for the sharper presentation, even with the 10–20% dip. If you’re hovering near your target frame rate, FSR 3 remains the safer pick for now.
This surge of community tinkering has sparked speculation that broader, official support could arrive down the line. If FSR 4 does get a sanctioned path on older GPUs, optimized implementations should trim overhead and improve stability compared to today’s modded DLLs. Until then, any use on unsupported hardware remains experimental—and very much at-your-own-risk.
